Granted Patent
Utility
US 5,158,434 · App. 07/813,190
Mixing impellers and impeller systems for mixing and blending liquids and liquid suspensions having a wide range of viscosities
Inventor:
Ronald J. Weetman
Patented Case
View Patent ↗
Granted: Oct 27, 1992
Filed: Dec 30, 1991
Inventor
Ronald J. Weetman
Assignee (at issue)
Federal Signal Corporation
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.